<a class="corner">ABC</a> 
<style> 

  .corner::before {
    position: absolute;
    top: 0.3rem;
    left: -1.5rem;
    z-index: 1;
    padding-right: 0.625rem;
    font-weight: bold;
    line-height: 0px;
    color: #000;
    height: 0px;
    border: 0.9375rem solid #ee7600;
    border-right-color: transparent;
    content: "新";
    box-shadow: 0px 0.3125rem 0.3125rem -0.3125rem #000;
  }

  /* .corner::after {
    content: "";
    position: absolute;
    top: 2.1875rem;
    left: -0.5rem;
    border: 0.25rem solid #89540c;
    border-left-color: transparent;
    border-bottom-color: transparent;
  }  */
  </style>